Electrical noise and interference affects the accuracy of electrical measurements, particularly in sensitive measurement circuits. For instance, excessive noise in a system can cause measurements of an electrical parameter, such as voltage or current, to appear random with time. In sensitive measurement circuits, in which small changes in a parameter are being measured, small amounts of noise can make a measurement unreliable. One known source for causing noise in a system is a power supply. For instance, main power supplies, such as a DC power supply, are known to introduce noise into a system. Furthermore, long electrical wires for electrically coupling the measurement circuit to the main power supply introduce interference into the system. Thus, main power supplies are known to affect the accuracy of sensitive measurement circuits.
Other systems for making analog to digital conversion include using switch-mode power converters to power the measurement circuits. Typically, the switch-mode power converter is used to provide the appropriate voltages required to power the measurement circuit and/or provide ground isolation. In general the system includes a main power supply, such as a AC-DC power supply or DC power supply, that is coupled to the switch-mode power converter. Unfortunately switching power supplies are inherently noisy and introduce a significant amount of noise into a measurement system affecting the accuracy of measurements made by sensitive measurement circuits.
Therefore, there is a need for a system that further reduces the effects of noise introduced in sensitive measurement circuits.